Geographic information systems provide for the archiving, retrieving, and manipulating of data that has been stored and indexed according to geographic coordinates of its elements. A geographic information system can be used for storing, manipulating, and displaying a graphical representation of a three-dimensional model of a geographic area. An interactive geographic information system can present the three-dimensional model of the geographic area to a user in a suitable user interface, such as a browser. A user can navigate the three-dimensional model by controlling a virtual camera that specifies what portion of the three-dimensional model is rendered and presented to a user.
The three-dimensional model can include a polygon mesh, such as a triangle mesh, used to model the geometry (e.g. terrain, buildings, and other objects) of the geographic area. Geographic imagery, such as aerial or satellite imagery, can be texture mapped to the three-dimensional model so that the three-dimensional model provides a more accurate and realistic representation of the scene. Typically, a single base texture is texture mapped to the polygon mesh regardless of the viewpoint of three-dimensional model. The single base texture can be optimized based on viewing the three-dimensional model from a plurality of differing viewpoints for the scene. For instance, the geographic imagery mapped to each polygon face (e.g. triangle face) in the polygon mesh can be selected according to a selection mechanism or algorithm that favors geographic imagery with a direct or near direct view of the polygon face. Given the varying orientations of the polygon faces in the mesh, the base texture typically is generated from base textures associated with a plurality of different view directions.
While the use of a single base texture can provide a realistic view of the three-dimensional model, certain visual artifacts can result from rendering a base texture optimized based on a plurality of different viewpoints in conjunction with the three-dimensional model. For instance, anomalies in the polygon mesh can become more readily apparent, in some cases giving the three-dimensional model a melted appearance. In addition, objects that are two small or too thin (e.g. cars, flag poles, streetlights, etc.) to be represented in the polygon mesh can lose their three-dimensional appearance.